Cooler module

ABSTRACT

A cooler module formed of a heat sink and a cooling fan is disclosed. A heat receiving base member of the heat sink has a flat bottom center contact surface and a plurality of bottom sloping surfaces (or one tapered bottom surface) obliquely upwardly extended from the border of the flat bottom center contact surface to the border of the heat receiving base member for spreading heat in all directions rapidly and evenly.

This application claims the priority benefit of Taiwan patent application number 097214105 filed on Aug. 6, 2008.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to cooling apparatus for cooling electronic components and more particularly, to a cooler module of which the heat receiving base member of the heat sink has a wall thickness gradually reducing from the center area that is in contact with the heat source toward the border for spreading heat in all directions rapidly and evenly.

2. Description of the Related Art

Following fast development of computer electronics technology, electronic devices are made having high computing power and speed. However, a high-speed electronic device releases much heat energy during operation. Heat accumulation may cause an electronic device to burn out. In order to effectively remove heat from a heat-releasing electronic device, a cooler module is usually used. A regular cooler module is comprised of a heat sink and a cooling fan. The heat sink absorbs heat from the heat source. The cooling fan forces air through the radiation fins of the heat sink to carry heat away. Heat dissipation surface area and radiation fin gaps affect the performance.

FIG. 10 illustrates a cooler module according to the prior art. According to this design, radiation fins A are bonded to the top wall of a receiving chamber B1 of a base member B. The base member B has two mounting flanges B2 arranged in parallel at two sides of the receiving chamber B1. Fastening members D are inserted through mounting through holes C1 of a fan C and fastened to respective mounting holes B21 on the mounting flanges B2 to affix the fan C to the base member B. To raise the heat transfer efficiency, copper is used for making the base member B.

The base member B is directly cut from a copper plate, and then bent into the desired shape. To save the processing cost, a copper plate having a rectangular cross section is usually used. When changing the cross-sectional shape of a copper plate, an extra processing process is needed, increasing the cost. Following rising of copper cost, the weight of the base member B becomes an important factor that affects the product cost. Therefore, increasing the thickness and area of the base member B relatively increase the cost of the heat sink. Further, when a heavy heat sink is used and attached to a heat source, for example, a CPU, the CPU may be damaged easily during an impact or vibration test, or during transportation of the computer using the CPU.

Further, modern CPUs have the characteristics of the characteristics of high performance and small size. When a heat sink having a relatively bigger and thicker base member is used, the heat transfer path from the heat source to the radiation fins of the heat sink will be relatively increased. When heat is spreading from the center area of the base member of a heat sink toward the border, a relatively greater heat transfer resistance will be encountered in case the base member has a uniform wall thickness, resulting in a temperature difference between the center area and the border area. Under this condition, the temperature difference between the radiation fins around the border area of the base member and the ambient air is insignificant, lowering the heat dissipation efficiency of the heat sink.

Therefore, it is desirable to provide a heat sink for cooler module that has the characteristics of low cost and high performance.

SUMMARY OF THE INVENTION

The present invention has been accomplished under the circumstances in view. It is one object of the present invention to provide a heat sink for cooler module that has the wall thickness of the heat receiving base member made gradually reducing from the center area toward the border, raising the heat transfer efficiency and enabling heat to be transferred from the heat source to the radiation fins evenly and rapidly for quick dissipation into the outside open air. It is another object of the present invention to provide a heat sink for cooler module that has the wall thickness of the heat receiving base member made gradually reducing from the center area toward the border, lowering the weight and material consumption.

To achieve these and other objects of the present invention, a cooler module is provided comprised of a heat sink and a cooling fan. The heat sink comprises a heat receiving base member and a plurality of radiation fins provided at the top side of the heat receiving base member. The heat receiving base member has a top wall that supports the radiation fins, and a bottom wall opposite to the top wall. The bottom wall comprises a flat contact surface for direct contact with a heat source, and a plurality of sloping surfaces obliquely upwardly extending from the border of the flat contact surface to the border of said heat receiving base member. By means of this design, the wall thickness of the heat receiving base member reduces gradually from the center area toward the border.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevational view of a heat receiving base member for heat sink according to the present invention.

FIG. 2 is a sectional side view of the heat receiving base member shown in FIG. 1.

FIG. 3 is an elevational view, showing a heat sink constructed according to the present invention and used with a radial fan.

FIG. 4 is a sectional side view, showing a heat sink constructed according to the present invention and installed in a circuit board.

FIG. 5 is an elevational view of an alternate form of the heat receiving base member for heat sink according to the present invention.

FIG. 6 is a temperature distribution diagram obtained from a thin type heat receiving base member constructed according to the present invention.

FIG. 7 is temperature-distance comparison diagram obtained from a regular rectangular base member for heat sink and a thin type heat receiving base member constructed according to the present invention.

FIG. 8 is a performance comparison chart, showing the performance of a regular rectangular base member for heat sink and the performance a thin type heat receiving base member constructed according to the present invention.

FIG. 9 is a thermal resistance-weight comparison diagram, showing the relative performance between a regular rectangular base member for heat sink and the performance a thin type heat receiving base member constructed according to the present invention.

FIG. 10 is a cooler module according to the prior art.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 1-3, a heat receiving base member 1 is shown for receiving heat from a heat source. The heat receiving base member 1 has a flat bottom center contact surface 11 that is in contact with the heat source, a plurality of bottom sloping surfaces 12 obliquely upwardly extended from the border of the flat bottom center contact surface 11 to the border of the heat receiving base member 1, a plurality of mounting through holes 13 respectively cut through the top and bottom sides in the corners thereof, a thin flange 14 extended from a first lateral side thereof, two eye lugs 15 extended from two distal ends of a second lateral side thereof opposite to the first lateral side, and two beveled edges 16 formed on the two distal ends of the first lateral side and the thin flange 14. Each eye lug 15 defines a through hole 151.

The heat receiving base member 1 can be made from copper, aluminum or their alloy by means of extrusion, die casting or forging, saving cutting cost in processing a rectangular metal block material into the desired shape. The design of the bottom sloping surfaces 12 diminishes consumption of the material and reduces the volume and weight of the heat receiving base member 1. Because the thickness of the heat receiving base member 1 gradually reduces from the flat bottom center contact surface 11 toward the border of the heat receiving base member 1, heat is transferred from the flat bottom center contact surface 11 toward the border of the heat receiving base member 1 rapidly. Therefore, the design of the present invention has the characteristics of light weight, low cost and high performance.

The design of the bottom sloping surfaces 12 can be designed to slop straightly or curvilinearly. According to this embodiment, the heat receiving base member 1 has four bottom sloping surfaces 12 respectively extended from the four sides of the flat bottom center contact surface 11. Alternatively, the heat receiving base member 1 can be made having only one tapered bottom sloping surface extending from the border of the flat bottom center contact surface 11.

Referring to FIG. 4 and FIGS. 1-3 again, radiation fins 2 are provided at the top side of the heat receiving base member 1 for dissipating heat. The heat receiving base member 1 and the radiation fins 2 constitute a heat sink. During application, the flat bottom center contact surface 11 of the heat receiving base member 1 is directly attached to the surface of a chip 31 on a circuit board 3, and fastening members 4 are respectively mounted in the mounting through holes 13 and fastened to the circuit board 3 to affix the heat receiving base member 1 to the circuit board 3. During operation of the chip 31, the heat receiving base member 1 receives heat from the chip 31 and transfers received heat to the radiation fins 2 for quick dissipation into the outside open air.

A cooling fan 5 is used to force air through the radiation fins 2, thereby carrying heat away. The cooling fan 5 according to this embodiment is a radial fan arranged at one side relative to the radiation fins 2. Alternatively, the cooling fan 5 can be used and directly mounted on the top side of the radiation fins 2 to force air vertically downwards through gaps between the radiation fins 2.

Before installation, a thermal compound or thermal adhesive glue can be applied to the flat bottom center contact surface 11 to eliminate possible gaps between the flat bottom center contact surface 11 and the surface of the chip 31 and to enhance the heat transfer performance of the heat receiving base member 1.

Referring to FIG. 5 and FIG. 1 again, the flat bottom center contact surface 11 can be made in the shape of a rectangular plane as shown in FIG. 1, or a circular plane as shown in FIG. 5. Alternatively, the flat bottom center contact surface 11 can be made having a rhombic or any of a variety of other shapes.

FIG. 6 is a temperature distribution diagram obtained from a thin type heat receiving base member constructed according to the present invention. FIG. 7 is temperature-distance comparison diagram obtained from a regular rectangular base member for heat sink and a thin type heat receiving base member constructed according to the present invention. FIG. 8 is a performance comparison chart, showing the performance of a regular rectangular base member for heat sink and the performance of a thin type heat receiving base member constructed according to the present invention. Following fast development of semiconductor technology, advanced IC chips have relatively higher performance and relatively smaller size. Further, the bottom base member of a conventional heat sink is a rectangular block member made from a metal material having high thermal conductivity. When the bottom base member of a heat sink is attached to a chip on a circuit board, only a limited center rear of the bottom wall of the bottom base member is kept in direct contact with the top surface of the chip, causing an effect of heat concentration. When heat is being transferred from the center of the bottom base member toward the border area, a certain heat transfer resistance is produced, lowering the heat transfer performance. To avoid this problem, the invention has the wall thickness of the heat receiving base member 1 made gradually smaller from the center area which is to be kept in direct contact with the heat source toward the border, lowering the heat transfer resistance. Therefore, the heat receiving base member 1 spreads heat in all directions rapidly.

Further, the design of the heat receiving base member 1 allows the number of the radiation fins 2 to be minimized. As shown in FIG. 8, the performance of a heat sink having a heat receiving base member constructed according to the present invention and 35 pcs radiation fins is substantially equal to the performance of a heat sink having a bottom base member of rectangular block type and 48 pcs radiation fins of the same specification. Therefore, a heat sink made according to the present invention has the characteristics of low weight and low cost.

Further, as shown in FIG. 7, the drop slope of the temperature drop curve obtained from a heat receiving base member 1 having a center thickness about 3.5 mm and a border thickness about 1 mm is lower than that of a rectangular block type heat receiving base member having a wall thickness 2.5 mm. When compared with a prior art heat sink, a heat sink constructed according to the present invention has a relatively higher performance while the weight is reduced by about 17%.

Further, the weight of the bottom base member of a heat sink is about 30%˜50% of the total weight of the heat sink. Therefore, a heat sink constructed according to the present invention can saves about 15% of the material weight.

As indicated above, the present invention has the following advantages and features:

1. The wall thickness of the heat receiving base member 1 gradually reduces from the center area (corresponding to the flat bottom center contact surface 11) toward the border. Therefore, when the flat bottom center contact surface 11 is attached to the chip 31 to transfer heat from the chip 31, heat energy is evenly distributed in the heat receiving base member 1 in all directions for quick dissipation through the radiation fins 2.

2. The heat receiving base member 1 is made from a metal material by means of extrusion, die casting or forging, no further cutting is necessary. Further, the sloping design of the bottom sloping surfaces 12 reduces material consumption. Therefore, the heat receiving base member 1 requires less material, saving the cost.

3. By means of the design of the bottom sloping surfaces 12, the volume and weight of the heat receiving base member 1 are minimized. Because the heat receiving base member 1 has a low weight, it does not cause damage to the chip 31 during an impact or vibration test, or transportation of the computer.

In conclusion, the invention provides a heat receiving base member 1 for heat sink, which has a flat bottom center contact surface 11 and a plurality of bottom sloping surfaces 12 (or one tapered bottom surface) obliquely upwardly extended from the border of the flat bottom center contact surface 11 to the border of the heat receiving base member 1. By means of this design, the heat receiving base member 1 spreads heat evenly and rapidly in all directions.

Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. 

1. A cooler module comprising a heat sink, said heat sink comprising a heat receiving base member for attaching to a heat source on a circuit board to transfer heat from said heat source and a plurality of radiation fins for dissipating heat from said heat receiving base member, wherein said heat receiving base member comprises a top wall supporting said radiation fins and a bottom wall opposite to said top wall, said bottom wall comprising a flat contact surface for direct contact with said heat source and at least one sloping surface obliquely upwardly extending from the border of said flat contact surface to the border of said heat receiving base member.
 2. The cooler module as claimed in claim 1, wherein said heat receiving base member comprises a plurality of mounting through holes cut through said top wall and said bottom wall in corners thereof for mounting fastening members.
 3. The cooler module as claimed in claim 1, wherein said heat receiving base member comprises two eye lugs protruded from two distal ends of a second lateral side thereof and each said eye lug has a through hole.
 4. The cooler module as claimed in claim 3, wherein said heat receiving base member further comprises a flange protruded from a first lateral side thereof opposite to said second lateral side, and two beveled edges formed on two distal ends of said first lateral side and two distal ends of said flange.
 5. The cooler module as claimed in claim 1, wherein said flat contact surface is a flat rectangular surface.
 6. The cooler module as claimed in claim 1, wherein said flat contact surface is a flat circular surface.
 7. The cooler module as claimed in claim 1, wherein said flat contact surface is a flat rhombic surface.
 8. The cooler module as claimed in claim 1, wherein said heat receiving base member is made from a metal material by means of one of the techniques of extrusion, die casting and forging.
 9. The cooler module as claimed in claim 8, wherein said metal material is selected from the group of aluminum, copper and their alloys.
 10. The cooler module as claimed in claim 1, further comprising a cooling fan mounted on said radiation fins at a top side.
 11. The cooler module as claimed in claim 1, further comprising a cooling fan provided at one side relative to said radiation fins. 